Ordered macroporous boron phosphate crystals as metal-free catalysts for the oxidative dehydrogenation of propane

Ordered macroporous materials with rapid mass transport and enhanced active site accessibility are essential for achieving improved catalytic activity.In this study,boron phosphate crystals with a three-dimensionally interconnected ordered macroporous structure and a robust framework were fabricated and used as stable and selective catalysts in the oxidative dehydrogenation(ODH)of propane.Due to the improved mass diffusion and higher number of exposed active sites in the ordered macroporous structure,the catalyst exhibited a remarkable olefin productivity of^16 golefin gcat^-1 h^-1,which is up to 2–100 times higher than that of ODH catalysts reported to date.The selectivity for olefins was 91.5%(propene:82.5%,ethene:9.0%)at 515℃,with a propane conversion of 14.3%.At the same time,the selectivity for the unwanted deep-oxidized CO2 product remained less than 1.0%.The tri-coordinated surface boron species were identified as the active catalytic sites for the ODH of propane.This study provides a route for preparing a new type of metal-free catalyst with stable structure against oxidation and remarkable catalytic activity,which may represent a potential candidate to promote the industrialization of the ODH process.

Promotion of boron phosphate on the NiMoAl catalyst for hydroprocessing FCC slurry oil

Mesoporous NiMoAl catalysts with boron phosphate(BPO4)modification were synthesized through the complete liquid-phase method.X-ray diffraction(XRD)analysis evidenced the presence of BPO4-AlOOH mixed support in these BPO4-modified NiMoAl samples.The total amount of acid sites declined,but the surface acidity was strengthened by adding BPO4 into the NiMoAl catalyst.It’s worth noting that the incorporation of BPO4 could increase the concentrations of Ni and Mo species on the catalyst surface and greatly improve the dispersion of(Ni)MoS2 active phases,as indicated by X-ray photoelectron spectroscopy(XPS)and transmission electron microscopy(TEM)measurements.The catalytic performance of these BPO_(4)-modified NiMoAl catalysts was investigated with the hydroprocessing of fluid catalytic cracking(FCC)slurry oil.The nitrogen-containing compounds removal from the oil was significantly enhanced with increasing the molar ratio of boron phosphate/aluminum.The NM-BPA(0.55)catalyst exhibited the best hydrodenitrogenation(HDN)activity,highlighting the significant impact of Mo sulfidation degree and the dispersion of active metals on HDN performance.The introduction of boron phosphate could also promote the hydrocracking activity of the NiMoAl catalyst,as demonstrated by SARA analysis and simulated distillation of liquid products.

A Highly Selective Metal-Free Boron-Based Catalyst for Oxidative Dehydrogenation of Ethylbenzene

Oxidative dehydroge nation of ethylbenzene is con sidered as an alter native route to styrene because of its exothermic and irreversible reaction nature,but encounters low styrene selectivity due to the deep-oxidation over metal oxide-based catalysts.Herein,we reported that a metal-free boron-based catalyst consisting of boron phosphate and boron nitride(BPO_(4)/BN)exhibited high activity and selectivity in oxidative dehydroge nation of ethylbenze ne to sty re ne.High selectivity of styre ne(95.1%)was achieved at 27.7%ethylbenzene conversion level over the optimized BPO_(4)/BN catalyst.The tetra-coordinated boron(BO_(4))species of BPO_(4) was speculated to be responsible for the ODH of ethylbenzene,and a synergistic effect between BPO4 and BN can remarkably improve the catalytic performance of the BPO_(4)/BN catalyst.The optimized BPO_(4)/BN catalyst showed a higher styrene formation rate of 4.0mmol g_(cat)^(-1)·h^(-1),compared individually to BPO_(4)(2.8mmol g_(cat)^(-1)·h^(-1))and BN(0.5mmol g_(cat)^(-1)·h^(-1)).